Efficient synthesis of silicon phthalocyanines (SiPc) eliminating the strenuous reaction conditions and hazardous reagents required by classical methods is described. Implementation into organic thin-film transistors (OTFTs) affords average electron field-effect mobility of 3.1 × 10−3 cm2 V−1 s−1 and threshold voltage of 25.6 V for all synthetic routes. These results demonstrate that our novel chemistry can lead to high performing SiPc-based n-type OTFTs.

Main-group phthalocyanines are an emerging class of organic semiconductors with versatile charge carriers in field-effect transistors. In this review, an overview is provided on the synthesis of these building blocks and device performances.

The perfluorinated analogue of silicon phthalocyanine (F2-F16SiPc) has been synthesized as a novel air-stable n-type organic semiconductor. The design of F2-F16SiPc facilitates strong electron conduction through peripheral fluorination that deepens...

Silicon phthalocyanines (SiPcs) are a class of n-type or ambipolar organic semiconductors that have been incorporated into organic thin-film transistors (OTFTs), organic light-emitting diodes (OLEDs), and organic photovoltaics (OPVs). Despite a relatively large catalogue of previously reported SiPc materials, fabricated OTFTs with these materials typically have threshold voltages (V T ) above 10 V, limiting their usage in commercial devices due to exceedingly high power consumption. Recent studies have suggested that the V T can be reduced in OTFTs prepared from phenoxy-substituted SiPcs by introducing electronwithdrawing groups onto the phenoxy moieties. Herein, we report the synthesis and characterization of three SiPcs with phenoxy axial substituents containing nitrile and fluorine functional groups. These SiPcs, along with 3,5-difluorophenoxy SiPc were evaluated as candidate materials for n-type OTFTs. We found that further increasing the electron-withdrawing character of the pendant phenoxy groups of the SiPc resulted in a significant decrease in average V T with the lowest reported value being 4.8 V, the lowest V T reported for a phenoxy-SiPc-based OTFT exceeding the previous record low of 7.8 V attributed to F 10 -SiPc. This decrease in V T could be directly correlated to the Hammett parameter of the axial functional groups. Furthermore, it was noted that dewetting occurred when the phenoxy pendant group of the SiPc was substituted at the para position with a nitrile group combined with orthoor meta-substituted fluorines, which was attributed to interactions at the semiconductor/dielectric interface. Depositing these SiPcs on silane-terminated poly(styrene) brush modified substrates improved long-term stability, demonstrated by a minimal change in surface morphology according to atomic force microscopy (AFM) images.

The functionalization of thiatriazinyl (TTA) radicals with pyridyl and thienyl moieties is described, and their influence at both the molecular and solid-state level has been investigated. Comparative electron paramagnetic resonance studies of 3,5-bis-(2-pyridyl)-1,2,4,6-thiatriazinyl (Py 2 TTA) and 3,5-bis-(2-thienyl)-1,2,4,6-thiatriazinyl (Th 2 TTA) reveal the impact of heteroaromatic substitution on the electronic structure, which is supported by density functional theory calculations. Single crystal X-ray analysis emphasizes the importance of intermolecular contacts on the crystal packing and demonstrates the potential for structural control through S---N′ and N---HC′ interactions, which are enhanced in Py 2 TTA and Th 2 TTA by the presence of the pyridyl and thienyl groups, respectively. This work represents a fundamental study of heterocyclic aromatic substitution in thiazyl-based radicals and investigates how varying these functional groups influences the molecular properties and long-range order within the supramolecular structure.